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Ohio State study: Microchips result in high rate of return of shelter animals to owners

COLUMBUS, Ohio – Animals shelter officials housing lost pets that had been implanted with a microchip were able to find the owners in almost three out of four cases in a recently published national study.

According to the research, the return-to-owner rate for cats was 20 times higher and for dogs 2 ½ times higher for microchipped pets than were the rates of return for all stray cats and dogs that had entered the shelters.

“This is the first time there has been good data about the success of shelters finding the owners of pets with microchips,” said Linda Lord, lead author of the study and an assistant professor of veterinary preventive medicine at Ohio State University.

“We found that shelters did much better than they thought they did at returning animals with microchips to their owners.”

Lord said that though the American public so far has not seemed to embrace the practice, this study suggests that pet owners should give strong consideration to microchipping their companion animals.

She also noted, however, that no animal identification is more effective than a tag on a collar that includes the pet’s name and the owner’s phone number.

Animal microchips are implanted at veterinary offices or shelters and contain a unique number that is revealed when the pet is scanned by a microchip detector. The number coincides with contact information that owners register with a microchip manufacturer.

“In the study, the biggest reason owners couldn’t be found was because of an incorrect or disconnected phone number in the registration database,” Lord said. “The chip is only as good as my ability as a pet owner to keep my information up to date in the registry.”
The research is published in a recent issue of the Journal of the American Veterinary Medical Association.

For the study, 53 shelters in 23 states agreed to maintain monthly records about microchipped animals brought to the facilities. Only shelters that automatically conduct scans for microchips on all animals were eligible to participate.

Data were collected from August 2007 to March 2008. The shelters reported outcomes for a total of 7,704 microchipped animals.

Strays made up slightly more than half of the animals tracked in the study, or 53 percent. About 42 percent of the animals had been surrendered by their owners, and were not factored into the return-to-owner rate.

The vast majority of microchips – 87 percent – were detected during a scan when the animals entered the shelter. About 10 percent were detected during a medical evaluation, and about 2 1/2 percent were detected just before the animals were scheduled for euthanasia or at some other time.

“We were able to backtrack this data and determine that 12 percent of microchips would have been missed without multiple scans,” Lord said. “We know from a prior study that there are good scanners on the market that can read all microchip frequencies out there. But like any technology, it’s not 100 percent. Many shelters now scan multiple times.”
In all, owners were found for 72.7 percent of microchipped animals. Among those found, 73.9 percent of the owners wanted the animals back in their homes.

“Is there room for improvement? Absolutely,” Lord said. “We really need to focus on not separating the microchip implantation process from registration. Veterinarians have a great opportunity at an annual wellness exam to scan a microchip and remind the owner of the need to keep information up to date in the registry. Likewise, when shelters implant microchips, they need to tell an adopter how it works and make sure information is in the registry before the animal leaves the building.”

In cases in the study in which owners were not found, the reasons included incorrect or disconnected phone numbers (35.4 percent), owners’ failure to return phone calls or respond to letters (24.3 percent), unregistered microchips (9.8 percent) or microchips registered in a database that differed from the manufacturer (17.2 percent).

Most people who obtain a microchip for their pet register their contact information with the chip’s manufacturer, Lord said. But a pet owner also can register with another company. In addition, many animal shelters keep their own microchip registry databases.

Because of these multiple registration options, Lord said a new Web site developed by the American Animal Hospital Association, (http://petmicrochiplookup.org), is likely to further improve the chances that owners of lost animals with microchips will be found. The site, launched in late September, performs a real-time lookup of a microchip number and determines which company has a registry for that microchip.

“The site will tell users that a microchip is registered with a specific database and list the registry number to call. And then you know you’ve got a hit,” Lord said. “This is an important development because it’s an easy-to-access, single place to find out where microchips are registered.”

She said that three of the six major registries in the United States are working with the organization, and additional participation is expected soon.

On average, only 1.8 percent of all stray dogs and cats taken to participating shelters had microchips. Lord said that though good statistics do not exist, veterinary experts estimate that microchips are used in between 5 percent and 8 percent of animals in the United States – mostly dogs, cats and horses.

“The number of microchipped pets will only grow,” Lord said, in part because animal shelters are increasing the practice of implanting microchips in every animal they adopt out to a new home.

“Shelters and veterinarians feel very strongly about doing everything they can to secure the human-animal bond,” Lord said. “Similarly, one of the paradigm shifts I am trying to accomplish is that if I as a veterinarian am trying to protect that pet and preserve that bond, keeping an animal in a home is a critical component. One component of the wellness conversation should be about identification options.”

The estimated cost to implant and register a microchip ranges from about $25 to $75, depending on where the service is performed.

Lord conducted this work with co-authors Walter Ingwersen of the pharmaceutical company Boehringer Ingelheim Canada’s Vetmedica Division; Janet Gray, a Redmond, Wash., veterinarian; and David Wintz of the Larimer Humane Society in Fort Collins, Colo. Ingwersen is a consultant for PetHealth Inc., the parent company of a microchip manufacturer. Lord has been a sponsored speaker at veterinary meetings by Bayer Animal Health and Intervet Schering-Plough Inc.